Field of the Invention
The present invention is concerned with the production of chemically modified starches, particularly tapioca starch used in puddings. In the past epichlorohydrin and propylene oxide routinely have been utilized to modify starch. Because of the possible undesirable health effects caused by the chlorohydrin residues suggested by recent studies, industry has been seeking ways to develop alternative chemically modified starches. One approach which has been followed is the use of an acetylated cross-linked starch which, for example, is a reaction product of acetic anhydride and phosphorus oxychloride with starch. In this process the starch is cross-linked (e.g., with phosphorus oxychloride, adipic anhydride or acrolein), and acetate esters are added to the basic starch back-bone. During the processing, various by-products are produced including sodium salts of acetates.
One of the drawbacks to the utilization of the foregoing modified starch in commercial formulations is the presence of detectable acetyl odors and the formation of off flavors. This is caused, it is thought, in-part, by a residual of sodium acetate remaining in the starch after processing.
It is the object of the present invention to produce an acceptable acetylated cross-linked starch having substantially no acetyl off flavors and odors by keeping them at undetected sub-threshhold levels both during storage and use in end products such as instant puddings.